This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Our research program is designed to utilize new types of macromolecular building blocks, based on branched DNA, as the basis of specific 3D structural designs. The goal of developing the systems is eventually to provide a macromolecular scaffolding, capable of binding, orienting and juxtaposing a variety of molecules, from cellular macromolecules to organic conductors and optical memory components. We propose to determine the structures of 3D periodic arrays, which represent the first designed 3D systems of this sort. These systems are likely to enable the initial crystallization of macromolecular species previously intractable to such ordering, and it is also designed to allow analysis of previously crystallized molecules bound to ligands whose presence disrupts their conventional lattices. The ability to produce specific structures on the nanoscale should also enable us to use this system to produce ordered arrangements of so-called cargo hetero-molecules that are attached to the DNA units. For example, the organization of nanoelectronic components in 3D, leading to smaller and presumably faster computation could likely result from this research